The present invention is directed to powered medical devices. In particular, the present invention relates to the repair and refurbishment of such powered medical devices.
Endoscopy in the medical field allows internal features of the body of a patient to be viewed without the use of traditional, fully invasive surgery. Endoscopic imaging systems enable a user to view a surgical site and endoscopic cutting instruments enable non-invasive surgery at the site.
Powered medical devices, including electrosurgical instruments, have been used together with endoscopy to cut and shape tissue at the surgical sites to which these instruments are applied. A typical electrosurgical instrument has an elongated shaft, sometimes called a “probe,” with a handle at one end and a tip at the opposed end. One type of electrosurgical instrument available to surgeons is referred to as a bipolar electrosurgical instrument. An active electrode is fitted into the tip of this instrument. The shaft of the bipolar electrosurgical instrument functions as the return or reference electrode. A generator provides energy to a distal end tip of a probe within the surgical site. In one mode, the probe provides energy at a power level to ablate or otherwise surgically remove tissue. In another instance, energy is provided to the probe in order to coagulate the tissue at the surgical site to minimize bleeding thereat.
Tissue ablation is achieved when a high power electrical signal having a sufficiently large voltage is generated by a control console and directed to an attached probe. Application of the high power signal to the probe results in a large voltage difference between the two electrodes located at the tip of the probe (presuming a bipolar probe). This large voltage difference leads to the formation of an ionized region between the two electrodes, establishing a high energy field at the tip of the probe. Applying the tip of the probe to organic tissue leads to a rapid rise in the internal temperature of the cells making up the neighboring tissue. This rapid rise in temperature near instantaneously causes the intracellular water to boil and the cells to burst and vaporize, a process otherwise known as tissue ablation. An electrosurgical “cut” is thus made by the path of disrupted cells that are ablated by the extremely hot, high energy ionized region maintained at the tip of the probe. An added benefit of electrosurgical cuts is that they cause relatively little bleeding, which is the result of dissipation of heat to the tissue at the margins of the cut that produces a zone of coagulation along the cut edge.
In contrast to tissue ablation, the application of a low power electrical signal having a relatively low voltage to the active electrode located at the tip of the probe results in coagulation. Specifically, the lower voltage difference established between the active and return electrodes results in a relatively slow heating of the cells, which in turn causes desiccation or dehydration of the tissue without causing the cells to burst.
The electrosurgical instruments described above and many other medical devices, both therapeutic and diagnostic, are electrically powered and include electrically powered control or sensing means. These devices may have only a limited useful life before repair or refurbishment is necessary. The limited lifetime of these devices is determined as the period during which the devices can be relied upon to perform well, after which the devices must either be replaced or serviced. Examples of limited-use therapeutic devices are electrosurgical operating instruments such as electrocautery surgical diathermies and hemostatic scalpels, endoscopic devices such as laparoscopic scissors and probes, arthroscopic operating instruments, angioplasty reaming instruments, and ultrasonic instruments. Examples of limited-use diagnostic devices are physiologic sensors, such as those used for the measurement or monitoring of physiological and biochemical parameters, (i.e. oxygen, glucose, etc.).
Accordingly, methods have been developed for accurately tracking the usage of a limited-use medical device. The ability to track device usage provides the capability for replacing or refurbishing a device before it fails, a vital consideration where the device is used in critical medical applications, such as surgical operations, or monitoring critically ill patients.
For example, powered medical devices may include a non-volatile memory device for tracking and accumulating usage data. In addition, a non-volatile memory device associated with a limited-use medical device may be used to automatically set the operational parameters (or other parametric data) for the limited-use device when the device is connected to a generator or other power supply, controller or measuring apparatus.
Alternatively, powered medical devices may include other electronic components that identify the medical device and indicate that the medical device has previously been used. For example, medical devices use one or more resistors that identify the medical device type when it is attached to a generator and one or more fuses that are selectively blown to indicate that the device has been used.
In certain powered medical devices, the non-volatile memory or other electronic components may be encapsulated inside a plug of the device. This configuration has several advantages, including compact size and increased protection for the electronic components. However, this arrangement also prevents the electronic components from being accessed for repair or refurbishment without cutting open or otherwise damaging the plug and destroying its integrity and usefulness.
Accordingly, a need exists for a method that allows repair or refurbishment of electronic components within the plug of a powered medical device without damaging the plug.
While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.